Certain types of ceramic capacitors are manufactured by laying up multiple thin layers of a ceramic insulator material alternating with thin electrically conductive layers. The conductive layer may, for example, take the form of a pattern screen printed with a conductive ink composition. The ceramic insulator layer is typically composed of inorganic and organic materials in an unfired or "green" form. The layered conductor/insulator structure is then heated fire or sinter the ceramic composition and the alternating layered conductor/insulator structure fuses into a monolithic article.
To facilitate handling during the manufacturing operation, an adhesive tape has been used to adhere a first green ceramic layer to a rigid carrier such as a metal plate. Then, alternating conductive layers and green ceramic insulating layers are stacked upon the first ceramic layer, and the layered structure is pressed and consolidated. Subsequently, the layered structure may be cut or diced to form individual discrete capacitors. Thereafter, the layered structures are fired or sintered to harden the ceramic and unite the layered structure.
In the manufacturing process, the adhesive tape is relied upon to firmly hold the layered structure to the carrier during the various processing steps of laying up, printing, dicing, etc. Before the ceramic articles have been fired however, they must be removed from the carrier without damage.
Conventional adhesive tapes used heretofore for this purpose have typically employed a heat curable adhesive. The adhesive loses its adhesive characteristic when heated under certain time and temperature conditions, thus allowing for release of the ceramic material from the adhesive tape. However, with this type of tape, the temperatures which can be used during the laminating or drying operations are limited by the properties of the tape. Laminating the ceramic layers at higher temperatures would better adhere the layers to one another. However, these higher temperatures that would help the ceramic layers adhere to one another can also cause the adhesive tape to prematurely release the ceramic articles from the carrier. Also, the time required to effect deactivation of the adhesive and release of the ceramic articles by heating is a limitation upon manufacturing throughput.
It is an object of the present invention to overcome the limitations of the prior conventional adhesive tapes just described. More particularly, it is an object of the present invention to provide an adhesive tape which can be used at higher temperatures than heretofore without allowing the tape to prematurely release from the carrier.